Ureteropelvic junction (UPJ) obstruction is the most common cause of congenital hydronephrosis, with an incidence of 4,000-10,000 infants annually. Preliminary data have identified demographic and regional variations in the imaging studies used to evaluate children with suspected UPJ obstruction and in the timing of surgery in children who undergo surgical treatment. The purpose of this project is to understand factors influencing treatment variations in infants with suspected UPJ obstruction. The central hypothesis is that differences in patient demographics and variations in radiographic evaluation are driving variations in treatment of infants with suspected UPJ obstruction. This project will establish a prospective, multi-center, observational cohort of infants by leveraging automatic data capture from the electronic health record (EHR) to support three related but independent aims. The first aim is to identify differences in the demographic and clinical issues guiding parents' and physicians' decisions for treatment using a series of semi-structured parent and physician interviews. The second aim is to compare the association between demographic characteristics and initial radiographic evaluation as well as likelihood of surgery in the first yar of life when controlling for differences in underlying clinical characteristics by using a multi-center prospective cohort of infants. The third aim is to assess the feasibility of a standardized clinical and radiographic evaluation across multiple clinical practices and, as a secondary endpoint, to assess the effect of standardized evaluation on demographic variations in initial treatment. Completion of these aims will provide a clearer understanding of the underlying etiology of non-clinical variations in treatment of these children, establish the feasibility of practice standardization across a multi-center research network, and provide the pilot data needed to support a R01 proposal that more clearly defines the association between surgery and kidney preservation to provide the data needed to develop evidence-based treatment guidelines for these patients. This project, coupled with guidance from her mentorship and graduate training in qualitative methods, EHR-based multi-center research network development and data analysis, and pragmatic clinical trial design and implementation will provide Dr. Vemulakonda with the foundation needed to successfully develop and implement large-scale multi-center studies and pragmatic trials to define the optimal role of surgery children with UPJ obstruction and other complex congenital urologic anomalies. This proposal addresses AHRQ's priority populations of children and minority groups and AHRQ's training goals of integrating quantitative and qualitative methods and using information systems to improve clinical decision making and practice. The approach is innovative in that it utilizes a mixed methods approach to understand the issues guiding surgical treatment, an approach not previously used in pediatric urology, and it leverages the EHR to facilitate the accurate capture of data entered by surgeons during routine clinical practice across multiple practices, overcoming previously identified barriers to multi-center surgical research. The proposal is significant in that improved understanding of non-clinical variations in treatment will help to reduce practice variability and improve the quality of care for these patients. Additionally, the development of a multi-center surgical research network facilitates investigation of the rare diseases that comprise the bulk of pediatric urologic practice. Future work will expand the multi-center research network established in this study to formally assess the role of surgery on short-term kidney outcomes, ultimately leading to a multi-center pragmatic randomized controlled trial to establish the optimal indications for surgical intervention in these children.